The cause was coronary artery disease, said his wife, Laura Parker, a journalist with whom he often collaborated and who is now a staff writer for National Geographic magazine.
Mr. Prochnau, a regular contributor to Vanity Fair for the past two decades, covered the Vietnam War for the Seattle Times and spent much of his early career writing about politics and national affairs for publications including The Washington Post. He also managed the successful 1974 reelection campaign of Sen. Warren G. Magnuson, a Democratic Party mandarin who had represented Washington state for what the reporter once described as “44 hard-drinking, cigar-smoking, syntax-chewing years.”
“On and off the floor, Magnuson fractured the English language in a way that made Mrs. Malaprop sound like a grammarian,” Mr. Prochnau wrote in The Post after his former boss lost reelection in a shocking upset in 1980. “Add this to a half-century career that evolved from early years of hell-raising and starlet-chasing into a mellowed-out, country-bumpkin version of a slightly eccentric granddaddy and Magnuson became something of an insider’s legend.”
Mr. Prochnau left The Post in the 1980s to focus on a second career as a freelancer and full-time author. His 1983 novel, “Trinity’s Child,” was a nuclear thriller adapted into a well-received HBO movie in 1990, “By Dawn’s Early Light,” starring James Earl Jones.
Mr. Prochnau spent 11 years working on “Once Upon a Distant War” (1995), a book examining how a new breed of aggressive young journalists — including David Halberstam of the New York Times and Neil Sheehan of United Press International — covered the United States’ deepening involvement in the Vietnam War with brash skill. Because of their impeccable on-the-ground reporting, they argued with military commanders giving optimistic estimates of the war’s progress and equally gung-ho editors back home.
Notable deaths in 2018 and 2019: Nipsey Hussle, George H.W. Bush, Stan Lee, John McCain, Aretha Franklin and other famous faces we’ve lost
The reporters he chronicled were not radicals but committed anti-communists, Mr. Prochnau once told the New York Times, “Cold War children, just like me, brought up on hiding under the desk.” But they did not countenance being “lied to” by the military authorities and few minced words about it.
In a Post review, journalist and Cold War historian Martin Walker called “Once Upon a Distant War” “a riveting account of that array of talented and ambitious young journalists who gathered in Saigon in the Kennedy years to make their names and record the coming disaster to American arms and American pretensions.”
William Walter Prochnau (pronounced PROCK-now) was born in Everett, Wash., on Aug, 9, 1937. He was 8 when his father died, and his mother, needing to support the family, became a nurse.
Mr. Prochnau attended Everett Community College and Seattle University and declined an offer to play minor-league baseball to focus on his burgeoning sportswriting career in Washington state and Alaska. He became the Seattle Times’s D.C. correspondent and co-wrote with Times reporter Richard W. Larsen “A Certain Democrat,” a 1972 biography of Sen. Henry M. “Scoop” Jackson of Washington state.
After working on Magnuson’s successful campaign for a fifth term in office, Mr. Prochnau helped found the short-lived Daily Journal-American in Bellevue, Wash., and later worked for the Seattle Post-Intelligencer as political editor and special projects reporter until joining The Post in 1980.
His first marriage, to Lani Gruger, with whom he had four children, ended in divorce. Their son, Mark Prochnau, died as a newborn in 1961, and their daughter Anna Prochnau died in 2015.
Besides Parker, his wife of 30 years, survivors include two daughters, Monica Bradley of Cocolalla, Idaho, and Jennifer McMaster of Spokane, Wash.; a brother; three grandchildren; and a great-granddaughter.
Mr. Prochnau began writing for Vanity Fair in 1996, on the recommendation of Halberstam. Former editor Graydon Carter wrote in an email that Mr. Prochnau “came at me back in the day with so many enticing ideas I would have been an idiot not to sign him up.”
The 2000 movie “Proof of Life,” starring Meg Ryan as the wife an engineer who is kidnapped in a fictional South American country and Russell Crowe as a hostage negotiator, was based in part on Mr. Prochnau’s 1998 Vanity Fair story “Adventures in the Ransom Trade,” about the big business behind kidnappings of executives of multinational companies.
Mr. Prochnau’s last published Vanity Fair story took more than 15 years to make it into print. It started with a query in 2002 from Carter, who had sent a clipping of an exhibit on an enigmatic adventurer named Oskar Speck in the Australian National Maritime Museum in Sydney.
The couple began piecing together a profile on Speck, a German who left his country in 1932 before Adolf Hitler came to power and kayaked 30,000 miles for 7½ years before landing in Australia.
“Speck stood five feet ten inches, and weighed a lean 140 pounds,” they wrote. “He couldn’t swim — and even traveling halfway around the world by ocean he never bothered to learn. He pushed off with little money, little planning, and only a vague goal of reaching Cyprus to find work in the copper mines.”
The story, written over several months, held and held — and held. The 9,000-word opus had no news value, Carter recalled in a post about his 25 years at Vanity Fair, but it was “a terrific tale and told perfectly.”
The story was published in the magazine’s February issue as “From Nazi Germany to Australia: The Incredible True Story of History’s Longest Kayak Journey.”
Read more Washington Post obituaries